The invention relates to an extension guide fitting for drawers comprising an extension rail at the drawer side, a carrier rail at the furniture body side, and a middle rail which runs between those two rails at both sides of the drawer. The load between the rails is transmitted by running rollers which are mounted in separate carriages. Mounted in the front region of the carrier rail is a stationary support roller on which the extension rail runs with a running limb and is supported at least in the closed condition of the drawer.
In the case of guide arrangements with running rollers which are mounted in their own carriages, the load-transmitting running elements (namely, the carriages with the rolling bodies) are disposed rather in the center of the guide system. In this connection, the term running rollers is used to denote rolling bodies quite generally, that is to say disc-shaped runner wheels, balls and rollers.
In the case of extension guide fittings with riveted running rollers, the load-transmitting elements are at the largest possible spacing from each other in the closed condition.
Therefore, extension guide fittings with running rollers which are mounted in carriages are more unstable in the closed condition than comparable extension guide fittings with riveted running rollers. That applies in particular in relation to full extension arrangements because they have one rail or running system more than partial extension arrangements.
The instability of the extension guide fitting makes itself felt adversely in the closed condition of the drawer in relation to the fronts of articles of furniture for several reasons. Firstly, the joints between fronts which are disposed in mutually superposed relationship are of different sizes, depending on the respective loading in the drawer or depending on respective production tolerances. Secondly, the fronts do not impinge against the front edge of the body of the article of furniture in parallel relationship, but come to bear against the front edge of the body of the article of furniture upwardly or downwardly, depending on the respective loading on the drawer or depending on respective production tolerances. It has therefore been proposed that, in the case of a full extension arrangement, a so-called run-on portion can be mounted on the drawer rail, the run-on portion running on to the carrier rail at the furniture body side, about 60 mm before reaching the closed position of the extension guide fitting or the drawer. In spite of an inclined run-on surface which is as gentle as possible, the moment at which the run-on portion runs on to the carrier rail can be clearly felt and is therefore perceived as undesirable.
Therefore, Austrian utility model AT 4518 U1 proposed arranging at the front end of each carrier rail a stationary support roller, whereby a gentler running-on movement of the drawer was achieved. That structure, however, did not prove worthwhile in relation to very heavy drawers.